Prepared in Cooperation with The U.S. Department of Agriculture Forest Service and New York City Department of Environmental Protection
SOIL-CALCIUM DEPLETION LINKED TO ACID RAIN AND FOREST GROWTH IN THE EASTERN UNITED STATES
CALCIUM CYCLING IN FORESTS Since the discovery of acid rain in the 1970's, scientists have been concerned that Calcium is an essential nutrient for tree growth deposition of acids could cause depletion of that is used in the formation of wood and in the calcium in forest soils. Research in the 1980's maintenance of cell walls, the primary structure showed that the amount of calcium in forest of plant tissue. Trees obtain calcium from the soil soils is controlled by several factors that are (fig. 1), but to be taken up by roots, the calcium difficult to measure. Further research in the (a positively charged ion) must be dissolved in soil 1990's, including several studies by the U.S. Geological Survey, has shown that (1) calcium in forest soils has decreased at locations in the northeastern and southeastern U.S., and (2) acid rain and forest growth (uptake of calcium from the soil by roots) are both factors contributing to calcium depletion.
s. Forest
Calcium in Soil Water \ Mineral Soil
Figure 1. Calcium cycle in forest ecosystems. Inputs to the pool of available calcium in the soil result from weathering of rocks, atmospheric deposition, and litterfall. Outputs from this pool result from root uptake and leaching out of the soil.
U.S. Department of the Interior WRIR 98-4267 J.S. Geological Survey February 1999 water. Calcium adsorbed to negatively charged adsorbed to particle surfaces. Weathering, the surfaces of soil particles (termed exchangeable physical and chemical breakdown of rocks, calcium) is also available to roots because both gradually releases calcium to soil water where it can adsorption and desorption of calcium occurs readily (1) be taken up by roots, (2) adsorb to particle through the process of chemical equilibrium. Some surfaces, or (3) be leached out of the soil by calcium is deposited onto forests in an available negatively charged ions in percolating water. form in dust and precipitation or is returned to the As calcium is released by weathering, acidity in the soil through decomposing leaves and branches that form of hydrogen ions is neutralized, which form the forest floor. Most of the calcium in soil, increases the pH of soil water and the surface waters however, is bound within the mineral structure of into which it flows. Calcium leached out of the soil rocks within the underlying mineral soil, which into surface waters also serves as an essential prevents it from dissolving in water or becoming nutrient for aquatic plants and animals.
CALCIUM RESEARCH IN THE 1970'S AND 80'S
The discovery of acid rain (acids deposited from increased leaching caused by acid rain (Johnson the atmosphere in rain, snow, particles and gases. and others, 1982). more accurately referred to as acid deposition) in the In the Southeast, the amount of calcium in soils 1970's prompted concern that deposition of acids was found to be generally less than in the could increase leaching of calcium, and other Northeast, but was thought to be somewhat neutralizing cations, such as magnesium, sodium, protected from cation leaching by the high and potassium (referred to as base cations) from capacity of these soils to adsorb sulfate, a forest soils. Acid deposition provides (1) hydrogen negatively charged ion. The fine texture of soils in ions, which displace cations adsorbed to soil the Southeast enhances sulfate adsorption, which surfaces, and (2) sulfate and nitrate ions, which tend removes the negative charge from soil water that is to keep these cations dissolved in soil water that necessary to leach the positively charged cations. eventually drains into streams and lakes. Results of Considerable uncertainty as to the status of soil preliminary research in the 1970's suggested that calcium remained, through the 1980's, however, elevated leaching might deplete soil calcium, because the processes involved in weathering and decrease forest growth, and acidify surface-waters leaching were found to be extremely complex. At (Cowling and Dochinger, 1980). These concerns the close of the research phase of the National were somewhat alleviated in the Northeast by the Acid Precipitation Assessment Program (NAPAP) discovery that the soil contained large amounts of in 1990, decreases in the availability of calcium in calcium. Although most of the soil calcium was forest soils from either acid rain or known to be in unavailable forms in rocks and forest growth had not been confirmed, although minerals, the rate at which calcium was released by the possibility of future depletion from acid weathering was considered to be sufficient to offset deposition was acknowledged (NAPAP, 1993).
CALCIUM RESEARCH IN THE 1990'S
Continued research in the 1990's has documented uptake of calcium by trees in excess of inputs from distinct decreases in soil calcium over the past 4 to 5 weathering. Follow-up studies have suggested, decades, in both the Northeast (Johnson and others, however, that both acid deposition (Markewitz and 1994a) and the Southeast (Richter and others. 1994). others. 1998) and a decline in deposition of calcium These decreases were attributed primarily to the from the atmosphere, a trend that has been underway since the 1970's, may also have contributed to the 1995; Long and others, 1997). Related studies have decrease in the availability of soil calcium in the also suggested that forest harvesting could reduce East (Johnson and others, 1994b). calcium availability through the removal of calcium Investigations of forest health have identified stored in trees, which could lower the growth rates of relations between low calcium availability and a the regenerating stand (Federer and others, 1989; reduction in stress tolerance of red spruce (Shortle Hornbeck and others, 1990). Relationships among and Smith, 1988; DeHayes, 1992; Schlegel and acid deposition, calcium availability, and forest others, 1992), and sugar maple (Wilmot and others, productivity remain uncertain, however.
Ongoing research hv the UfS, Geological Sutviy, in collaboration with the U.S. Fbre&l Service, the University of Illinois, the Institute of Ecosystem Stitdtes and Syracuse University, has provided tw information on the causes cind magnitude of calcium depletion In $wfy of the- eastern United States, Remits of this research have been tlt>ttiilt'd in four articles prepared for scientific. jewriMls. A general summary of each of these articles and a vf current USGS cnkwm meareh fallows.
1. DISCOVERY OF A NEW MECHANISM OF CALCIUM DEPLETION IN FOREST SOILS
Aluminum released to water in the mineral soil by acid rain decreases the availability of calcium in the overlying forest floor, the primary layer for nutrient uptake by roots in forest soils. Lawrence, G.B., David, M.B., Shortle, W.C., 1995, A new mechanism for calcium loss in forest-floor soils; Nature, v. 378, p. 162-164. Decreases in concentrations of exchangeable by capillary movement. Because aluminum has a calcium are generally attributed to displacement by much higher affinity for negatively charged surfaces hydrogen ions, which can originate from either acid than calcium, introduction of aluminum into the deposition or uptake of cations by roots (Johnson forest floor tends to displace adsorbed calcium, and others, 1994a, Richter and others, 1994). A which causes it to be more readily leached. A regional survey of soils in northeastern red spruce continued buildup of aluminum in the Oa horizon forests in 1992-93 (fig. 2) has revealed that can (1) decrease the availability of calcium for roots decreases in exchangeable calcium concentrations in (Lawrence and others, 1995), (2) lower the the Oa horizon (a layer within the forest floor, efficiency of calcium uptake because aluminum is where uptake of nutrients is greatest) can also result more readily taken up than calcium when the ratio of from increased concentrations of exchangeable calcium to aluminum in soil water is less than 1 aluminum, which originated in the underlying (Cronan and Grigal, 1995), and (3) be toxic to roots mineral soil (Lawrence and others, 1995). By at high concentrations (Anderson, 1988). lowering the pH of the aluminum-rich mineral soil, The Oa horizon has generally been considered acid deposition can increase aluminum immune from acidification by acid deposition concentrations in soil water through dissolution and because the typical pH of soil water in this horizon is ion-exchange processes. Once in solution, the less than 3.8 whereas the pH of rain in the East aluminum (although not a nutrient) is taken up by typically ranges between 4.0 and 4.5 (lower pH roots and transported through the trees to be indicates greater acidity). The low pH of soil water eventually deposited on the forest floor in leaves in the Oa horizon is caused by organic acids that and branches. Dissolved aluminum in the mineral form naturally through the decomposition of plant soil can also be transported into the forest floor by a matter. Organic acids that move downward in rising water table, or during unsaturated conditions, percolating water from the Oa horizon into mineral 1. Kossuth, Me. horizons, which contain little organic 2. Bear Brook, Me. 3. Howland, Me. matter, tend to be removed from solution 4. Crawford Notch, N.H. through further decomposition or by 5. Bartlett, N.H. adsorption to mineral surfaces. Once 6. Cone Pond, N.H. 7. Hubbard Brook, N.H. removed from solution, they are incapable 8. Sleepers River, Vt. of acidifying the soil, which results in a 9. Groton, Vt. 10. Mt. Abraham, Vt. higher pH in the mineral soil than in the 11. Whiteface Mountain, N.Y. forest floor. Unlike these natural organic 12. Big Moose Lake, N.Y. acids, sulfuric and nitric acids from acid 13. Neversink River, N.Y. 14. Great Smoky Mts. Nat. Park deposition neither decompose (because 15. Oak Ridge, Tn. they are inorganic) nor adsorb to soil 16. Calhoun Forest, S.C. particles readily; rather, they tend to remain in solution within the mineral soil where they lower the pH, thereby releasing aluminum to soil water and causing the leaching of calcium. The effects of these processes can be seen through a comparison of soils that
17. Shenandoah National Park have been acidified to varying degrees 18. Duke Forest, N.C. (table 1). The ratio of exchangeable 19. Panola Mountain, Ga. aluminum to exchangeable calcium in the 20. Coweeta Hydrologic Lab, N.C. 21. StewartCo., Ga. Oa horizon was lowest at Groton, Vt, where 22. Clemson, S.C. the pH of water in the mineral soil was 23. Gainesville, Fl. highest, and the pH of soil water in the Oa horizon was lowest. At Big Moose Lake, N.Y. and Mt. Abraham, Vt. the pH of soil water in the B horizon was considerably lower than at the Groton site and the ratios of exchangeable aluminum to exchangeable calcium in the Oa horizons were greater
Figure 2. Locations at which soil-calcium assessments than 1.0, the threshold above which have been made in the papers by Lawrence and others, aluminum can interfere with uptake of (1995,1997) and Huntington and others (USGS approved). calcium by roots.
Table 1 . pH and ratio of exchangeable aluminum to exchangeable calcium (AI:Ca) in soil water from forest floor (Oa horizon) and mineral soil (upper 10 centimeters of B horizon) in three red spruce stands of the northeastern United States. Forest floor Mineral soil Site location PH AI:Ca* PH AI:Ca*
Groton, Vt. 3.3 0.3 4.8 5 Big Moose Lake, N.Y. 3.5 1.2 4.1 27 Mt. Abraham, Vt. 3.7 5.6 4.1 16 * ratio expressed as centimoles of charge per kilogram Aluminum per centimole of charge per kilogram Calcium 2. STATUS OF SOIL CALCIUM IN THE OA HOftlZON OF RED SPRUCE STANDS OF THE NORTHEAST
A regiomd assessment offa rest-sod chemistry supports evidence of soil-calcium depletion in the Northeast; acid rain identified as a probable factor. Lawrence, G..B., David, M.B., Bailey, S,W., Shortle, W.C.J997, Assessment of calcium status in soils of red spruce forests in the northeastern United States: Biogeochemisiry, v. 38, p. 19-39.
Decreases in available calcium in forest soils of spruce stands in the Adirondack Mountains of New the Northeast have been indicated in several studies York, was near the middle of the range obtained by in the 1990's (Shortle and Bondietti, 1992; Bailey Lawrence and others (1997), and in the upper range and others, 1996; Johnson and others, 1994a;b), but of values obtained in a study by McNulty and others the results of these studies could not be directly (1991). The average value obtained for Adirondack related to each other because the measurements of sites measured by Heimburger (1934) 50 years soil-calcium concentrations were made with earlier was in the upper part of the range measured different methods of unknown comparability. To by Lawrence and others (1997). Although address this problem, soil samples collected by considerable variability was caused by local Lawrence and others (1995) in the survey of red differences in environmental factors such as spruce forests (fig. 2) were analyzed by the four mineralogy of parent material, and acid deposition most common methods currently used for measuring rates, the results support the probability indicated by exchangeable calcium (Lawrence and others, 1997). the combined studies of Johnson and others A comparison was also done between the most (1994a;b), Shortle and Bondietti (1992), Lawrence common current method for determining acid- and others (1995), and Bailey and others (1996), that extractable calcium and the method used by concentrations of available calcium in northeastern Heimburger (1934), and also by Johnson and others red spruce forests have decreased in the second half (1994a) in resampling the plots first sampled by of this century. Heimburger 50 years earlier (Lawrence and others, 1997). The soil survey of Lawrence and others 1992-93 (1995, 1997) in red spruce forests entailed the 1987-88 selection of 12 sites that together encompassed the 1984 1930-32 range of environmental conditions represented by red spruce stands in the Northeast. 0 10 20 30 40 50 60 70 80 90 100 110 Considerable variability in exchangeable-calcium Acid-Extractable Calcium, in millimoles per kilogram concentrations was observed among the 12 sites; EXPLANATION concentrations ranged from 2.1 to 22.0 centimoles of Mean concentrations of calcium in soils of individual charge per kilogram in the Oa horizon, and from sites in New York, Vermont, New Hampshire and Maine sampled by Lawrence and others (1997) in 1992-93. 0.11 to 0.68 centimoles of charge per kilogram in the upper mineral soil. The primary cause of this A Mean concentrations of calcium in soils of individual sites in New York, Vermont, New Hampshire and Maine variability was mineralogical differences in parent sampled by McNulty and others (1991) in 1987-88. material (rock that weathers to form soil), but results also suggested that acidic deposition had decreased O Mean concentrations of calcium in soil of 38 samples collected by Heimburger (1934) throughout the concentrations of exchangeable calcium in the Adirondack Mountains of New York in 1930-32. mineral soil at these sites (Lawrence and others, 1997). O Mean concentrations of calcium in soil of 59 samples Results of the methods-comparison tests were collected by Johnson and others (1994a) throughout used to relate the long-term decrease documented in the Adirondack Mountains of New York in 1984. the study by Johnson and others (1994a) to the range of calcium variability measured in the study by Figure 3. Acid-extractable calcium in Oa horizons of red spruce stands in the studies of Lawrence and others Lawrence and others (1997). The average value (1997), McNulty and others (1991), Heimburger (1934), determined by Johnson and others (1994a) for 38 red and Johnson and others (1994a). 3. DEPLETION OF SOIL CALCIUM AFFECTS THE RESPONSE OF STREAM CHEMISTR TO DECLINING RATES OF ACID DEPOSITION IN THE NORTHEAST
Relations among acid deposition rates, base-cation concentrations in soils, and stream-water acidification indicate that changes in soil-calcium status can affect long-term trends in stream chemistry. Lawrence, G.B., David, M.B.. Lovett, G.M., and others, In Press, Soil-calcium status and the response of stream chemistry to changing acidic deposition rates in the Catskill Mountains of New York: Ecological Applications.
Rates of acid deposition have been declining in 50° A. Atmospheric deposition o Lll the Northeast since the 1970's, but many acidified 450 surface waters in the region have unexpectedly shown little or no corresponding increase in acid- neutralizing capacity, an integrated measure of the CO ~ DC 200 degree to which a water body is acidified. Long- 150 term records of stream chemistry at the Hubbard
Brook Experimental Forest in New Hampshire (fig. LJJ I_LJ UJ 2) showed that the ratio of base cations (calcium, CO _l Q_ O LL « < 5 O LJJ 1.5 magnesium, sodium, and potassium) to acid anions LJJ DC O I- ^ CD CD o 1- DC ^ 1 ® e (sulfate, nitrate and chloride) decreased steadily Z Z < < BASE- LJJ z @® 0 & LJJ I LOGRA through the 1970's, then remained fairly stable I O O 0.5 O z O through the 1980's and early 1990's (Likens and X o Z LL LJJ o O 0 others, 1996). This response was interpreted as an ^ indication that past declines in soil concentrations of z" C. Soil bags collected after 1 year LJJ CO DC O 0.7 z o LJJ LJJ CO calcium and other base cations were impeding m Q_ 0.6 O LL 9 Initial concentration " <
4. CALCIUM DEPLETION IN FOREiST ECOSYSTEMS OF THE SOUTHEAST
Data from detailed site studies and regional surveys suggest that soil-calcium depletion is common in forests of the Southeast and could diminish long-term forest productivity. Huntington, T.G., Hooper, R.P., Johnson, C.E., Aitlenbach, B.T., and Cappellato, A., in review, Calcium depletion in forest ecosystems of the southeastern United States: Submitted for publication as an article in a technical journal (USGS Approved).
Accumulating evidence indicates possible inputs from weathering and atmospheric deposition depletion of soil calcium in forests of the were found to be insufficient to replenish the losses Southeast, as well as the Northeast. Long-term that occur through uptake by vegetation and studies at several southeastern forest sites have leaching (Johnson and others, 1988; Johnson and documented declines in the exchangeable-calcium others, 1991; Knoepp and Swank, 1994; Richter concentration of soils. In these studies, calcium and others, 1994). Several factors suggest that the available calcium watershed was in the middle of the range of values in southeastern soils is prone to depletion. These reported for other forested sites in the Southeast. soils have weathered in place for a few hundred Lower availability of calcium in soils of the thousand to 2 million years and many of them have Southeast than the Northeast is suggested by surveys little weatherable calcium left in soil particles and of exchangeable calcium concentrations in soils. rocks. Also, poor farming practices caused About 70 percent of the sites sampled in the extensive loss of soil and nutrients on lands that are Southern Blue Ridge region through the U.S. EPA now used for commercial forestry (Nelson, 1957; Direct-Delayed Response Program (Church and Brender, 1974; Trimble, 1974). Forest growth others, 1989) had concentrations of exchangeable places a continued demand on the remaining calcium less than 1000 kilograms per hectare, calcium in these soils, and when the stands are whereas in the Northeast, about 50 percent of the harvested, the calcium in the trees is removed from the ecosystem. Acidic deposition during the 20th A. SOIL 100 century has placed further strain on soil calcium C/D LU availability by enhancing calcium leaching rates at a H - Southern Blue time when the rates of atmospheric deposition of C/D Ridge Province LL 80 (n = 99) calcium have declined (Lynch and others, 1996). O LU The potential for calcium depletion in southern CD forest soils, was evaluated in detail through the i^ 60 ..* /* Northeast LJJ development of a calcium budget for Panola Mountain O (n = 280) watershed, in the Piedmont region near Atlanta, Ga. £40cc (Huntington and others, USGS approved); this budget LJJ was then compared with data from other watershed studies and soil surveys to assess the extent of calcium f] 20 depletion within the Southeast. Calcium-budget =) =) calculations for Panola Mountain watershed (averaged O over the roughly 90 year life of the current forest 0 1000 2000 3000 4000 5000 6000 stand), indicate that the rate of calcium leaching from EXCHANGEABLE SOIL CALCIUM, the soil approximates the rate of calcium input from IN KILOGRAMS PER HECTARE atmospheric deposition. Also, chemical and B. STREAM WATER mineralogical analyses of soil and saprolite (the highly 100 C/D weathered layer of residual rock beneath the soil) LJJ H Southern Blue Ridge Province indicated that only trace amounts of weatherable C/D LL 80 mineral calcium remain, which suggests that inputs O LU from weathering are negligible. The annual rate of CD calcium depletion in this watershed is, therefore, F 60 Southern Appalachians similar to the annual rate of uptake by trees of 10.7 LJJ O kilograms per hectare. Continuous depletion at this oc rate for 150 years would reduce the total reserves of £40 calcium in the soil to the approximate amount required LJJ by a hardwood stand to reach a marketable size. fj 20 Budget calculations for other forested study sites in the Southeast showed a wide variation in O sensitivity to soil-calcium depletion (table 2). The 250 500 750 1000 1250 1500 most sensitive forests are dominated by hardwood CALCIUM CONCENTRATION, species, which have a higher calcium demand than IN MICROEQUIVALENTS PER LITER softwoods; at some sites more calcium is contained by the trees than by the soil. Stands that are the Figure 6. Cumulative percentage of sites as a function of least sensitive tend to be dominated by softwood (A) exchangeable calcium concentrations in soil and (B) calcium concentrations in stream water in selected and are in areas that receive the highest amounts of regions of the eastern United States. Figure A adapted calcium from atmospheric deposition. The rate of from Turner and others (1993); Figure B adapted from calcium depletion estimated for Panola Mountain Sale and others (1988). sites sampled had calcium concentrations less than Southeast, in conjunction with the surveys of soil 1000 kilograms per hectare (fig. 6a). Calcium and stream chemistry, suggest that (1) depletion of concentrations in southeastern streams also tended to calcium in soils is common, (2) the growth of some be distributed toward low values, as indicated by the forests may be limited by insufficient amounts of steeply ascending lines in fig. 6b. calcium in soils, and (3) calcium availability will be The assessments of the calcium budgets at Panola lowered by forest harvesting of sites currently low Mountain watershed and other forested sites in the in calcium.
Table 2. Calcium (Ca) contents of soil, calcium fluxes, net calcium depletion, and sensitivity to calcium depletion at selected forest sites in the eastern United States. [kg/ha, kilograms per hectare; (kg/ha)/yr, kilograms per hectare per year; ND, no data) Calcium content Calcium flux of soil (kg/ha) [(kg/ha)/yr] Ecosystem Net Total Leach" Net sensitivity Source Type of Exchange- uptake by deposi- ing from Calcium to Calcium of Site location forest able Total trees tion soil depletion depletion3 datab
A. Sites that are highly sensitive to calcium depletion
Great Smoky Beech 57 2,500 7.5 6.3 14.7 highc Mountains Nat. Park Oak Ridge, Tenn. Oak 140 1,800 8 5.4 I 3.6 highc 2 Oak Ridge, Tenn. Oak 110 1,180 17 5.4 12 23.6 highc 2 Calhoun Forest, S.C. Pine 245 ND 7.5 2.8 10.2 14.9 highc 3 Shenandoah Nat. Mixed pine, 380 ND 10d 3.9 2.7 8.8 highc 4 Park, Va. hardwood Oak Ridge, Tenn. Pine 820 2,500 16 5.4 15 25.6 highc 2 Coweeta Hydrologic Mixed 1,370 11,500 12.2 7.1 1.5 6.6 high 97 1 Laboratory, N.C. hardwood
B. Sites that are moderately sensitive to calcium depletion Stewart Co.; Ga. Pine 840 840 6 3.2 1.1 3.9 med. 123 6 Duke Forest, N.C. Pine 2.130 4,900 13.6 8.1 8.1 13.6 med. 130 1 Panola Mountain, Ga. Mixed pine, 2,200 2,200 10 2.25 2.9 10.7 med. 150 5 w hard wood C. Sites that are insensitive to calcium depletion Clemson, S.C. Pine 1,450 ND 3.4 2.9 3.9 4.4 low 310 7 Oak Ridge, Tenn., Pine 6,900 8,600 5.5 5.4 19.2 19.3 low 350 1 plot 1 Gainesville, Fla. Pine 240 758 5.9 8 2.1 0 low6 1 Coweeta Hydrologic Pine 667 3,770 3.9 7.1 2.2 -1 low6 1 Laboratory, N.C. Great Smoky Spruce 230 1,800 1.2 19 10 -7.8 low6 1 Mountains Nat. Park
1 Value indicates number of years until current rates of depletion reduce exchangeable stores to twice the expected requirement for a marketable forest stand 3 References: 1. Johnson and Lindberg, 1992; 2. Johnson and Todd, 1990; 3. Richter and others, 1994. 4. Written commun. from J.R. Webb (University of Virginia), June 1995. 5. Huntington and others (USGS approvedO; 6. Huntington, 1996b; 7. Johnson and others, 1988. ; Soils already depleted to less than twice the calcium requirement for marketable timber Estimated from typical forest growth rates in this area, on basis of USDA Forest Service Forest Inventory Analysis data and calcium concentration for oak (Quercus spp.) Either soils are accumulating calcium, or output equals input UNANSWERED QUESTIONS
Much information has been obtained in the 1990's 2. How do rates of soil-calcium weathering and on the calcium status of forest soils in the East, but leaching vary throughout the East? additional work is needed to define the current trends in soil calcium availability and to determine if 3. How is forest growth affected by low levels of these trends will continue into the future. Some available calcium? specific questions that need to be addressed are: 4. How does forest harvesting affect the 1. Is the available calcium content of soils currently availability of soil calcium and long-term trends in increasing, decreasing, or remaining stable? stream chemistry?
ONGOING USGS RESEARCH
Unanswered questions regarding the current and and Young Womens Creek, in Pennsylvania.) and future status of calcium in the East are being two in the Southeast (Little River, in Tennessee, and addressed through the USGS Hydrologic Benchmark Cataloochee Creek, in North Carolina). These Network (HBN) and the National Trends Network investigations will (1) measure atmospheric (NTN). The HBN sponsors monitoring of stream deposition rates, stream chemistry, and soil flow and chemistry, in undeveloped, medium-sized chemistry, (2) determine soil-weathering rates, basins (100 to 200 km2 drainage areas). The NTN, forest-growth history and past harvesting in these which is closely affiliated with the National watersheds, and (3) assess the effects of future tree Atmospheric Deposition Program (NADP), supports harvesting. A primary objective of this work is to the monitoring of chemical deposition in rain and gather detailed information on calcium cycling that snow (wet-only deposition) at about 100 locations can be used to assess current conditions for each of nationwide. The HBN and NTN programs are the five basins. This information will be integrated currently supporting investigations in three HBN with the long-term monitoring data to better watersheds in the Northeast (the Wild River, in New understand past and future changes in soil-calcium Hampshire and Maine, the Neversink River, in N.Y., status in the eastern United States.
REFERENCES CITED
Anderson, M., 1988, Toxicity and tolerance of Church, M.R., Thornton, K.W., Shaffer, and others, aluminum in vascular plants: Water, Air and Soil 1989, Direct/delayed response project: future Pollution, v. 39, p. 439-462. effects of long-term sulfur deposition on surface Bailey, S.W, Hornbeck, J.W., Driscoll, C.T., and water chemistry in the Northeast and southern Gaudette, H.E., 1996, Calcium inputs and trans Blue Ridge Province, level I and level II analysis: port in a base-poor forest ecosystem as interpreted National Acid Precipitation Program, Washington, by Sr isotopes: Water Resources Research, v. 32, D.C., EPA/600/3-89/061b. p. 707-719. Cronan, C.S., and Grigal, D.E, 1995. Use of cal Brender, E.V., 1974, Impact of past land use on cium/aluminum ratios as indicators of stress in the lower Piedmont forest: Journal of Forestry, forest ecosystems: Journal of Environmental v. 72, p. 34-36. Quality, v. 24, p. 209-226. Cowling, E.B., and Dochinger, L.S., 1980, Effects of causing soil changes: Journal of Environmental acidic precipitation on health and productivity of Quality, v. 19, p. 97-104. forests: USDA Forest Service Technical Report, Johnson, D.W, Turner, J., and Kelly, J.M., 1982, The PSW-43, 165-173. effects of acid rain on forest nutrient status: Water DeHayes, D.H., 1992, Winter injury and develop Resources Research, v. 18, p. 449-461. mental cold tolerance of red spruce: in Eager, C. Knoepp, J.D., and Swank, W.T., 1994, Long-term and Adams, M.B., (eds.), Ecology and decline of soil chemisty changes in aggrading forest red spruce in the eastern United States, New York, ecosystems: Soil Science Society of America, Springer-Verlag, p. 295-337. v. 58, p. 325-331. Federer, C.A., Hornbeck, J.W, Tritton, and others, Lawrence, G.B., David, M.B., Bailey, S.W.. and 1989. Long-term depletion of calcium and other Shortle. W.C., 1997, Assessment of calcium status nutrients in eastern U.S. forests: Environmental in soils of red spruce forests in the northeastern Management, v. 13, p. 593-601. United States: Biogeochemistry, v. 38, p. 19-39. Heimburger, C.C., 1934, Forest-type studies in the Lawrence, G.B., David, M.B., Lovett, G.M., and Adirondack Region: Ithaca, N.Y., Cornell Univer others, in press, Soil-calcium status and the sity Agriculture Experiment Station Memoir 165. response of stream chemistry to changing acidic Hornbeck, J.W, Smith, C.T., Martin, and others, deposition rates in the Catskill Mountains of 1990. Effects of intensive harvesting on nutrient New York: Ecological Applications. capitals of three forest types in New England: Lawrence, G.B., David, M.B., and Shortle, W.C., Forest Ecology and Management, v. 30, p. 55-64. 1995. A new mechanism for calcium loss in Huntington, T.G., 1996, Assesssment of the potential forest-floor soils: Nature, v. 378, p. 162-164. role of atmospheric deposition in the pattern of Likens, G.E., Driscoll C.T., and Buso, D.C., 1996, southern pine beetle infestation in the northwest Long-term effects of acid rain: response and Coastal Plain Province of Georgia, 1992-95: U.S. recovery of a forest ecosystem: Science, v. 272, Geological Survey Water-Resources Investiga p. 244-246. tions Report 96-4131, 75 p. Long, R.P., Horsley, S.B., and Lilja, P.R., 1997, Johnson, A.H., Anderson, S.B., and Siccama, T.G., Impact of forest liming on growth and crown 1994a, Acid rain and soils of the Adirondacks. 1. vigor of sugar maple and associated hard Changes in pH and available calcium: Canadian woods: Canadian Journal of Forest Research, Journal of Forest Research, v. 24 p. 193-198. v. 27, p. 1560-1573. Johnson, A.H., Friedland, A.J., Miller, E.K., and Lynch, J.A., Bowersox, V.C., and Grimm, J.W, Siccama, T.G., 1994b, Acid rain and soils of the 1996. Trends in precipitation chemistry in the Adirondacks. III. Rates of soil acidification in a United States: 1983-1994, and analysis of the montane spruce-fir forest at Whiteface Mountain, effects in 1995 of Phase I of the Clean Air Act New York: Canadian Journal of Forest Research, Amendments of 1990, Title IV: U.S. Geological v. 24, p. 663-669. Survey Open File Report 96-0346. Johnson, D.W., Cresser, M.S., Nilsson, S.I., and Markewitz, D., Richter, D.D., Alien, H.L. and others, 1991. Soil changes in forest ecosystems: Urrego, J.B., 1998, Three decades of observed evidence for and probable causes: Proceedings of soil acidification in the Calhoun Experimental the Royal Society of Edinburgh, v. 97B, p. 81-116. Forest: Has acid rain made a difference?: Soil Johnson, D.W.. Henderson, G., andTodd, D., 1988, Science Society of America Journal, v. 62, Changes in nutrient distribution in forests and p. 1428-1439. soils of Walker Branch Watershed, Tennessee, McNulty, S.G., Aber, J.D. and Boone, R.D., 1991, over an eleven year period: Biogeochemistry, Spatial changes in forest floor and foliar v. 5, p. 275-293. chemistry of spruce-fir forests across New Johnson, D.W., and Lindberg, S.E., 1992, Atmo England: Biogeochemistry, v. 14, p. 13-29. spheric deposition and forest nutrient cycling, NAPAP (National Atmospheric Precipitation New York, Springer-Verlag. Assessment Program), 1993: 1992 Report to Johnson, D.W., and Todd, D.E., 1990, Nutrient Congress. Washington, D.C. cycling in forests of Walker Branch watershed, Nelson ,T.C, 1957, The original forests of the Tennessee roles of uptake and leaching in Georgia Piedmont: Ecology, v. 38 p.390-397.
(11 Richter, D.D., Markewitz, D., Wells, and others, Shortle, W.C., and Smith, K.T., 1988, Aluminum- 1994, Soil chemical change in an old-field loblolly induced calcium deficiency syndrome in declining pine ecosystem: Ecology, v. 75, p. 1463-1473. red spruce trees: Science, v. 240, p. 1017-1018. Sale, M.J., Kaufmann, P.R., Jager, H.I., and others, Trimble, S.W., 1974, Man-induced soil erosion in 1988, Chemical characteristics of streams in the the southern Piedmont: Ankeny, Iowa, Soil mid-Atlantic and southeastern United States Conservation Society of America. volume 2 (Streams sampled, descriptive statistics Turner, R.S., Brandt, C.C., Schmoyer, D.D., and and compendium of physical and chemical data): others, 1993, Direct/Delayed Response Project Washington, B.C., U.S. Environmental Protection Data Base: Oak Ridge National Laboratory, Agency, EPA/600/3-88/021b, 595 p. Environmental Sciences Division, BSD Publica Schlegel, H., Amundson, R.G., and Hueterman, A., tion No. 2871, 107 p. 1992, Element distribution in red spruce (Picea Wilmot, T.R., Ellsworth, D.S., and Tyree, M.T., rubens) fine roots; evidence for aluminum toxicity 1995, Relationships among crown condition, at Whiteface Mountain: Canadian Journal of growth, and stand nutrition in seven northern Forest Research: v. 22, p. 1132-1138. Vermont sugarbushes: Canadian Journal of Forest Shortle, W.C., and Bondietti, E.A., 1992, Timing, Research, v. 25, p. 386-397. magnitude, and impact of acidic deposition on sensitive forest sites: Water, Air and Soil Pollution, v. 61, p. 253-267.
By 'Gregory B. Lawrence and 2T. G. Huntington
For more information contact: This report and related information can be found on the World Wide Web at: 1 Gregory B. Lawrence 2 T.G. Huntington http://bqs. usgs.gov/acidrain U.S. Geological Survey U.S. Geological Survey 425 Jordan Rd. 3039 Amwiller Rd. Additional earth science information can Troy, NY 12180 Atlanta, Ga 30360 be obtained by accessing the USGS "Home E-mail address: E-mail address: Page" on the World Wide Web at: glawrenc @ usgs.gov [email protected] http://water, usgs.gov
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